export default "\nuniform vec2 u_Range;  // [min, size]\nuniform lowp sampler2D u_Palette;\nuniform lowp float u_Alpha;\n\nlowp vec4 colorize(in float v) {\n    vec2 st = vec2((fmap(v) - u_Range.x) / u_Range.y, 0.5);\n    lowp vec4 color = texture2D(u_Palette, st);\n    lowp float alpha = (1.0 - step(NIL, v)) * u_Alpha;\n    return vec4(color.rgb * alpha, alpha);  // premultiply alpha\n}\n";